"Short List" for Parson's Problem with Scratch Blocks

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Introduction

Today, we have released a new feature called “short list”, which can be used by teachers to easily create parson’s problems as coding exercises.

The “short list” is simply a list of blocks in the block palette, which can be dragged into the playground:

 
Note that the short list is part of a project. When you create a new project, its short list is empty. When you remix a project or save a copy of it, the new project keeps the same short list of blocks as the original project. This makes the short list very different from the Backpack at the bottom, which remains the same for the same user across all projects.

 
 

Adding blocks to the short list

 

There are 2 ways to add blocks to the short list.

For the first method, you can click the “Add blocks from editor” button, which will add all the blocks currently used in the playground (for this sprite only) to the short list:

 
This is the fastest way to add blocks to the short list. Note that the blocks on the short list are all unique, so the same block will only appear once on the list.

For the second method, you can right-click (or long-press on touchpads) on any block and select “add to short list”, which will add that block to the short list, and also any other blocks attached below it:

 
 

Removing blocks to the short list

 

To remove blocks from the short list, you can either click the remove icon next to any block, or use the “Clear list” button to remove all blocks on the list:

 
 

About Parson’s Problems

 

A Parson’s problem is a coding puzzle where the blocks needed are given to the student, so the student only needs to put them together into a working program. Research has found that Parson’s problem is a very effective tool for teaching new programming languages.

Specifically, here are the key benefits of using Parson’s Problems:

• Reduced Difficulty: when working with a Parson’s problem, it is much easier for students to determine which blocks to use, since the list of blocks is very short.

• Time Savings: students no longer to go through different categories to find the blocks they need, since they are all given as one short list.

• Block Choice Control: the teacher can specify which blocks the students can use when designing a Parson’s problem. For example, if a teacher wants a student to use the “move N steps” block instead of the “change x by N” block, they just need to make sure only the former block is included in the short list.

 

 

 

 

 

 

 

 
 

Demo - Creating a Parson’s Problem Using the Short List

 

Now let’s try to create a Parson’s problem for testing the student how to use the “move N steps” block.

 
 

Step 1 - Create a Solution Program

 

First, let’s write a working program that demonstrates how to use the “move N steps” block to move the sprite to the left. We should test run it to make sure it works as expected:

 
 

Step 2 - Add Blocks to the Short List

 

Next, we can decide which blocks we want the students to use. It does not have to be all the blocks. In this example, suppose we want the student to focus on the blocks starting with the “point in direction” block. We can add only those blocks to the short list (make sure the short list is cleared first). After that, we can remove these blocks from the program.

 
 

Step 3 - Add Instructions as Comments

 

Next, we can use the “Add Comment” tool to add some instructions for the students. Note that the comment is in rich text format on CreatiCode, so you have great control on text formatting, and you can even add images.

 
 

Step 4 - Reset Sprite State

 

One of the requirements is to make the sprite move left, which means the student must first point it in the direction of -90 degrees. We should set the sprite to 90 degrees by default, so the program will not work if the student fails to use that block:

 
 

Step 5 - Share the Project with Students

 

For the last step, we can share this project with our students. If it needs to be protected, we can use a password:

 
 

Step 6 - Students remix the project

 

For a student, after opening this project, they can remix it. The new project will have the same starting blocks and short list. After the students complete the challenge, they can share their project with their teacher.